Peter A Goldsbury
Well, we had a discussion about this in the dojo last night, after training. All the participants (all native Japanese except me) thought that it was a mistake, either for 隙がない (suki ga nai) or for another phrase entirely, such as 傍が甘え. (waki ga amae). This last phrase means that one's defences are weak and is clearly opposite in meaning to what is intended by the original phrase.
Thank you for your reply, Professor. I also immediately thought of 隙がない , but didn't consider a misquote.